Date: Sun, 25 Nov 2001 15:36:56 -0800 From: Kris Kennaway <kris@obsecurity.org> To: Ian Dowse <iedowse@maths.tcd.ie> Cc: Kris Kennaway <kris@obsecurity.org>, cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/usr.bin/tail forward.c Message-ID: <20011125153656.A94203@xor.obsecurity.org> In-Reply-To: <200111252321.aa42920@salmon.maths.tcd.ie>; from iedowse@maths.tcd.ie on Sun, Nov 25, 2001 at 11:21:02PM %2B0000 References: <20011125144540.A93369@xor.obsecurity.org> <200111252321.aa42920@salmon.maths.tcd.ie>
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--mP3DRpeJDSE+ciuQ Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sun, Nov 25, 2001 at 11:21:02PM +0000, Ian Dowse wrote: > In message <20011125144540.A93369@xor.obsecurity.org>, Kris Kennaway writ= es: > > > >Hmm, this strikes me as a bit nasty...ideally you shouldn't have to > >poll for any status changes in a kqueue world. Is there an easy way > >kq could be improved to handle this? >=20 > I guess tail could add a kevent for every component in the specified > path including expanded symlinks (and resort to polling if any were > on filesystems that don't support kqueue). I think that would just > over-complicate tail for very little real gain. Note that tail -f > doesn't use polling; it's only when you explicitly tell tail that > the path might change by specifying "-F" that it gets used. I > suppose for -F, the timeout could be increased to 5 or 10 seconds > also because simple renames within the same directory are noticed > immediately. I dunno..the major use of tail -F is probably on logfiles which get rotated infrequently. I can imagine that a site might want to simultaneously monitor a large number of logfiles, but I don't know what the CPU impact of that with your change would be..maybe not much. If you tail -F, say, 100 simultaneous files, how much CPU does that stat'ing use? Kris --mP3DRpeJDSE+ciuQ Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.6 (FreeBSD) Comment: For info see http://www.gnupg.org iD8DBQE8AYCEWry0BWjoQKURAh9xAJ9ZnqHFZxDNCFa1TFQ2iHQJj44+8wCfSKbF 2gKE0XwXcsCKtxbpHrYvXy0= =XYIn -----END PGP SIGNATURE----- --mP3DRpeJDSE+ciuQ-- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message
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